<html>
<head>
	<meta charset="UTF-8">
	<meta content="IE=edge" http-equiv="X-UA-Compatible">
	<meta content="initial-scale=1.0, maximum-scale=1.0, user-scalable=no, width=device-width" name="viewport">
	<title>2357：化学反应</title>
	<!-- css -->
	<link href="../css/base.min.css" rel="stylesheet">
	<link href="../css/project.min.css" rel="stylesheet">
	
	<!-- favicon -->
	<!-- ... -->
</head>
<body class="page-brand">
	<header class="header header-transparent header-waterfall ui-header">
		<ul class="nav nav-list pull-left">
			<li>
				<a data-toggle="menu" href="#menu">
					<span class="icon icon-lg">menu</span>
				</a>
			</li>
		</ul>
		<a class="header-logo header-affix-hide margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">化学反应</a>
		<span class="header-logo header-affix margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">化学反应</span>
	</header>
	<nav aria-hidden="true" class="menu" id="menu" tabindex="-1">
		<div class="menu-scroll">
			<div class="menu-content">
				<a class="menu-logo" href="../index.html">BZOJ离线题库</a>
				<ul class="nav">
					<li>
						<a class="waves-attach" data-toggle="collapse" href="#problems">题目</a>
						<ul class="menu-collapse collapse in" id="problems">
							<li>
								<a class="waves-attach" href="../index.html">主页</a>
							</li>
							<li>
								<a class="waves-attach" href="../list.html">题目列表</a>
							</li>
						</ul>
					</li>
					<li>
						<a class="collapsed waves-attach" data-toggle="collapse" href="#about">关于</a>
						<ul class="menu-collapse collapse" id="about">
							<li>
								<a class="waves-attach" href="../about.html">关于此项目</a>
							</li>
						</ul>
					</li>
					
				</ul>
			</div>
		</div>
	</nav>
	<main class="content">
		<div class="content-header ui-content-header">
			<div class="container">
				<h1 class="content-heading">
                化学反应                </h1>
                <p>时间限制：3s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
		</div>
		<div class="container">
			<section class="content-inner margin-top-no">
				<div class="row">
					<div class="col-lg-13 col-md-13">
						<div class="card margin-bottom-no">
							<div class="card-main">
								<div class="card-inner">
									
                                <h3>题目描述</h3><p><div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">给定</span><span style="font-size: 12pt; line-height: 200%">K</span><span style="font-size: 12pt; line-height: 200%">种化学物质和</span><span style="font-size: 12pt; line-height: 200%">N</span><span style="font-size: 12pt; line-height: 200%">种反应类型。每个反应都有一些反应物和生成物，且反应需要一定的时间。假设每次反应后的若干生成物都可以完全分离。而每次反应的生成物，可以立即用于其他反应的生成物。每种物质的数量都是无限的。</span></div>
<div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">给出一些已有的物质，求得到一种指定物质至少要多少时间。</span></div></p><hr/><h3>输入格式</h3><p><div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">第一行包含</span><span style="font-size: 12pt; line-height: 200%">4</span><span style="font-size: 12pt; line-height: 200%">个整数，分别为</span><span style="font-size: 12pt; line-height: 200%">K</span><span style="font-size: 12pt; line-height: 200%">、</span><span style="font-size: 12pt; line-height: 200%">N</span><span style="font-size: 12pt; line-height: 200%">、已有物质数量</span><span style="font-size: 12pt; line-height: 200%">M</span><span style="font-size: 12pt; line-height: 200%">和所求物质的编号；</span></div>
<div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">下面依次是</span><span style="font-size: 12pt; line-height: 200%">N</span><span style="font-size: 12pt; line-height: 200%">种反应的描述。每种反应的描述有三行。第一行包含一个正整数，表示该反应的时间；第二行第一个数是这个反应的反应物的数量，接着是这些反应物的编号；第三行第一个数是生成物的数量，接着是生成物的编号。</span></div>
<div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">已有物质的编号总是</span><span style="font-size: 12pt; line-height: 200%">1</span><span style="font-size: 12pt; line-height: 200%">到</span><span style="font-size: 12pt; line-height: 200%">M</span><span style="font-size: 12pt; line-height: 200%">，编号为</span><span style="font-size: 12pt; line-height: 200%">M+1</span><span style="font-size: 12pt; line-height: 200%">到</span><span style="font-size: 12pt; line-height: 200%">K</span><span style="font-size: 12pt; line-height: 200%">的为开始时没有的物质。</span></div></p><hr/><h3>输出格式</h3><p><div style="text-indent: 24.1pt; line-height: 200%"><span style="font-size: 12pt; line-height: 200%">包含一个非负整数，表示生成指定的物质需要的最短的时间。如果无法生成指定物质，则输出</span><span style="font-size: 12pt; line-height: 200%">-1</span><span style="font-size: 12pt; line-height: 200%">。</span></div>
<p></p></p><hr/><h3>样例输入</h3><pre>4 3 1 4
8
1 1
1 4
3
1 1
2 2 3
2
2 1 3
1 4
</pre><hr/><h3>样例输出</h3><pre>5
</pre><hr/><h3>提示</h3><p><p>【样例说明】<br />
依次进行反应二和反应三，可以得到所有种类的物质，耗时为5.<br />
【数据规模】<br />
&nbsp;<br />
30%的数据满足，1&lt;=K,N&lt;=10；<br />
100%的数据满足，1&lt;=K&lt;=250，1&lt;=N&lt;=500.</p></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
								</div>
							</div>
						</div>
					</div>
				</div>
				
				
			</section>
		</div>
	</main>

	<div class="fbtn-container">
		<div class="fbtn-inner">
			<a class="fbtn fbtn-lg fbtn-brand-accent waves-attach waves-circle waves-light waves-effect" data-toggle="dropdown" aria-expanded="true"><span class="fbtn-text fbtn-text-left">Menu</span><span class="fbtn-ori icon">apps</span><span class="fbtn-sub icon">close</span></a>
			<div class="fbtn-dropup">
				<a class="fbtn fbtn-brand waves-attach waves-circle waves-light waves-effect" href="../list.html" target="_self"><span class="fbtn-text fbtn-text-left">题目列表</span><span class="icon">menu</span></a>
				<a class="fbtn fbtn-green waves-attach waves-circle waves-effect" href="../index.html" target="_self"><span class="fbtn-text fbtn-text-left">返回主页</span><span class="icon">home</span></a>
				<a class="fbtn waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=2357" target="_blank"><span class="fbtn-text fbtn-text-left">提交代码</span><span class="icon">send</span></a>
				<a class="fbtn fbtn-orange waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/wttl/wttl.php?pid=2357" target="_blank"><span class="fbtn-text fbtn-text-left">试题讨论</span><span class="icon">chat</span></a>
				
			</div>
		</div>
	</div>

	<!-- js -->
	<script src="../js/jquery.min.js"></script>
	<script src="../js/base.min.js"></script>
	<script src="../js/project.min.js"></script>
</body>
</html>